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https://issues.apache.org/jira/browse/FLINK-32133?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17724268#comment-17724268
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Liu commented on FLINK-32133:
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A related issue is https://issues.apache.org/jira/browse/FLINK-10848.
> Batch requests and remove requests in the end to reduce YarnResourceManager's
> excess containers
> -----------------------------------------------------------------------------------------------
>
> Key: FLINK-32133
> URL: https://issues.apache.org/jira/browse/FLINK-32133
> Project: Flink
> Issue Type: Improvement
> Components: Deployment / YARN
> Affects Versions: 1.18.0
> Reporter: Liu
> Priority: Major
>
> h1. Problem
> When the initial job requests many containers from yarn, it is easy to get
> more than needed containers for that the YARN AM-RM protocol is not a delta
> protocol (please see YARN-1902). For example, we are needing 3000 containers.
> Consider the following case.
> *Case one:*
> # The job requests 2000 containers firstly and the the yarn client has 2000
> requests.
> # {color:#FF0000}The yarn heartbeat happens and the yarn client +request
> 2000 containers+ to yarn rm.{color}
> # The job requests another 1000 containers and the the yarn client has 3000
> requests.
> # {color:#FF0000}The yarn heartbeat happens and the yarn client +request
> 3000 containers+ to yarn rm.{color}
> # On heartbeat finish, yarn rm {+}returns 2000 containers{+}. After the
> callback the method onContainersAllocated and removeContainerRequest, yarn
> client has 1000 requests.
> # {color:#FF0000}The yarn heartbeat happens and the yarn client +request
> 1000 containers+ to yarn rm. {color}
> # On heartbeat finish, yarn rm {+}returns 3000 containers{+}. After the
> callback the method onContainersAllocated and removeContainerRequest, yarn
> client has 0 requests.
> # {color:#FF0000}The yarn heartbeat happens.{color}
> # On heartbeat finish, yarn rm +returns 1000 containers+{color:#FF0000}
> {color:#172b4d}which are excess since the last client request number is
> 1000.{color}{color}
> {color:#172b4d}In the end, the yarn may allocate 2000 + 3000 + 1000 = 6000
> containers. But we only need 3000 containers and should return 3000
> containers.{color}
> *{color:#172b4d}Case two:{color}*
> # {color:#172b4d}The job requests 3000 containers firstly and the the yarn
> client has 3000 requests.{color}
> # {color:#FF0000}The yarn heartbeat happens and the yarn client +request
> 3000 containers+ to yarn rm.{color}
> # On heartbeat finish, yarn rm {+}returns 1000 containers({+}2000
> allocating{+}){+}. After the callback the method onContainersAllocated and
> removeContainerRequest, yarn client has 2000 requests.
> # {color:#FF0000}The yarn heartbeat happens and the yarn client +request
> 2000 containers+ to yarn rm.{color}
> # On heartbeat finish, yarn rm {+}returns 2000 containers{+}. After the
> callback the method onContainersAllocated and removeContainerRequest, yarn
> client has 0 requests.
> # {color:#FF0000}The yarn heartbeat happens.{color}
> # On heartbeat finish, yarn rm +returns 2000 containers+{color:#FF0000}
> {color:#172b4d}which are excess since the last client request number is
> 2000.{color}{color}
> {color:#172b4d}In the end, the yarn may allocate 1000 + 2000 + 2000 = 5000
> containers. But we only need 3000 containers and should return 2000
> containers.{color}
> {color:#172b4d}The reason is that any update to the yarn client's requests
> may produce undesired behavior. {color}
> h1. {color:#172b4d}Solution{color}
> {color:#172b4d}In our inner flink version, we use two ways to resolve the
> problem as following:{color}
> # {color:#172b4d}{color:#172b4d}Compute the total resource requests at start
> and request by batch{color}{color}{color:#172b4d} to avoid being interrupted
> by yarn heartbeat. Note that we {color}{color:#172b4d}{color:#172b4d}loop
> {color}{color}resourceManagerClient.addContainerRequest(containerRequest){color:#172b4d})
> to simulate batch-request quickly.{color}
> # {color:#172b4d}Remove the yarn client's container requests after receiving
> enough resources to avoid request update.{color}
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